A Novel Dimeric Butenolide, Glochidiolide, from the Leaves of Glochidion Acuminatum MUELL.
A novel dimeric butenolide called glochidiolide was isolated from the leaves of Glochidion acuminatum. Its structure was elucidated by X-ray analysis.
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Dehydration and Rehydration of Vermiculites: IV. Arrangements of Interlayer Components in the 1.43 nm and 1.38 nm Hydrates of Mg-Vermiculite
Article Dehydration and Rehydration of Vermiculites: IV. Arrangements of Interlayer Components in the 1.43 nm and 1.38 nm Hydrates of Mg-Vermiculite was published on January 1, 1998 in the journal Zeitschrift für Physikalische Chemie (volume 207, issue 1-2).
Thermal and spectroscopic characterization of polypyrrole formed in zeolite Y
Encapsulation of pyrrole in two kinds of zeolite Y (NaY and USY) with various concentrations of CuII ions has been attempted by a gas diffusion process, and the products have been characterized by means of thermoanalytic and spectroscopic methods. From the results, it was found that the progress of polymerization depe…
Laminated bus bars for power system interconnects
This paper demonstrates the effects of a laminated busbar on power electronics circuits, and compares its characteristics to those of other power distribution topologies. Included in the discussion are physical as well as electrical characteristics, along with the manufacturing implications that need to be considered.
Alkyl-substituted Schlenk hydrocarbon diradicals with triplet and singlet ground states in frozen solutions
Ground states for alkyl-substituted Schlenk hydrocarbon diradicals 1–4 in frozen 2-MeTHF or THF are determined at low temperatures by EPR spectroscopy (4–80 K) or SQUID magnetometry (2–80 K). Diradicals 1, 2, and 3 are triplet ground states. Diradical 4 is the singlet ground state with the singlet–triplet gap, ΔEST ≈…
Self-association of branched and dendritic aromatic amides
Several branched and dendritic aromatic amides have been obtained by reacting tris(4-aminophenyl)methane 3 either with aryl iodide 1 in a Pd-catalysed carbonylation or with carboxylic acids in the presence of the coupling agent triphenyl phosphite. Nonpolar aromatic substituents and solubilising groups at the peripher…
Grain-boundary shearing as a test for interface melting
We examine the behaviour of the (310) symmetric tilt boundary with applied shear stress in a face-centred cubic Lennard-Jones crystal. Our purpose is to observe the mechanical properties of grain boundaries resulting from interface melting. The grain boundary is seen to exhibit significant self-diffusion at temperatur…
CONVENIENT SYNTHESIS OF DIFURYLMETHANES AND DITHIENYLMETHANES AND THEIR APPLICATION TO THE SYNTHESES OF CORE-MODIFIED PORPHYRINS
One flask synthesis of dithienylmethane and difurylmethane is reported. The reaction of aldehydes with excess furan or thiophene affords the meso-phenyldithienylmethane (DTM) and meso-phenyldifurylmethane (DFM), respectively. The reaction is catalyzed with trifluoroacetic acid or with BF3·O(Et)2. An acyl group is sele…
A Hydrogen Problem in Fusion Material Technology
Hydrogen is considered one of the major problems for ferritic and martensitic steel structures in future fusion reactors. In contrast to hydrogen from other sources, hydrogen produced by nuclear transmutations cannot be kept away by barriers but must be drained off through the surfaces. An upper limit of the diffusion…
Calcium‐Ion Selective Site Occupation at Ruddlesden‐Popper‐Type Faults and the Resultant Dielectric Properties of A‐Site‐Excess Strontium Calcium Titanate Ceramics
The microstructure and dielectric properties of A‐site‐excess and stoichiometric‐composition strontium calcium titanate ((Sr,Ca)TiO 3 ) ceramics were investigated in the present study. Ruddlesden‐Popper‐type planar faults in A‐site‐excess specimens were observed using high‐resolution scanning transmission electron mic…
In situ observation of structural changes in polycrystalline silver catalysts by environmental scanning electron microscopy
Morphology changes induced in polycrystalline silver catalysts as a result of heating in either oxygen, water or oxygen–methanol atmospheres have been investigated by environmental scanning electron microscopy (ESEM), FT-Raman spectroscopy and temperature programmed desorption (TPD). The silver catalyst of interest co…
Effect of surfactant and pH on the redox potential of microperoxidase 11 in aqueous micellar solutions
The redox potential of heme undecapeptide from cytochrome c (microperoxidase 11) in aqueous sodium dodecyl sulfate (sds), hexadecyltrimethylammonium bromide, and Triton X-100 surfactant micelles varied from +2 mV at pH 3.0 to –222 mV at pH 9.0. The potentials at pH 7.0 were –114, –122, and –166 mV vs. the normal hydro…
Inference of PD in electrical insulation by charge-height probability distribution. Diagnosis of insulation system degradation
This paper deals with application of stochastic procedures for the analysis of PDHD (partial discharge height distributions) detected during life of insulation systems. Experiments of accelerated aging under electrical stress were carried out on both an artificial flat cavity and a 23 kV epoxy-resin insulator, where P…
Spectroscopic studies of the chemical speciation in concentrated alkaline aluminate solutions
The 205Tl NMR and UV/VIS spectral changes associated with the hydrolysis of thallium(I) have been employed to investigate hydroxide-sensitive equilibria in highly concentrated alkaline aluminate solutions {0.1 M < [Al(III)]T < 2.6 M; 0.15 M < [NaOH]T < 4.0 M} in an ionic medium of 8 M Na(ClO4) at 25 °C. Spectroscopic…
Synthesis and electrochemical properties of tetrathiafulvalene derived amino acids and peptides
A synthetic route to a tetrathiafulvalene (TTF) derived aspartic acid derivative 18, with suitable orthogonal protecting groups has been developed. The aspartic acid derivative 18 can be used in the synthesis of peptides, as exemplified by the synthesis of di-, tri- and tetra-peptides 21–23. Preliminary electrochemica…
Convenient, low energy routes to hexagonal ferrites MFe12O19(M=Sr, Ba) from SHS reactions of iron, iron oxide and MO2 in air
Thermal initiation of a mix of metal superoxide (MO2 , M=Sr, Ba), iron and iron powder in air induces a self propagating reaction with velocity 0.5 mm s–1 and the formation of predominantly MFe12O19 . Heating the mixture to 1150 °C for 2 h produces pure crystalline MFe12O19 . The ferrites were characterised by X-ray p…
ION-EXCHANGE ISOTHERMAL SUPERSATURATION
The paper describes the new phenomenon called Ion-Exchange Isothermal Supersaturahon (IXISS). This effect is observed for a number of ion-exchange systems, where frontal or reverse frontal separation is accompanied by the formation of stable supersaturated solutions of slightly soluble substances in the interstitial s…
Dielectric study of KNbO3ceramics over a large range of frequency (102-109Hz) and temperature (300-800 K)
KNbO3 ceramics were sintered at 1263K thanks to a LiF additive. The ferroelectric-paraelectric transition is of first order and occurs at T c∼670K. A dielectric study in a large frequency range (102-109Hz) shows: –a strong frequency dispersion of the permittivities at low frequency for T > 500 K which comes mainly fro…
Kinetic and mechanistic study of the pressure and temperature dependence of the reaction CH3O+NO
New kinetic measurements for the CH3O + NO reaction have been performed using two different techniques. The discharge flow (DF) technique has been used to investigate the 0.5–5 Torr and 248–473 K pressure and temperature ranges and pulsed laser photolysis (PLP) has been used for the 30–500 Torr and 284–364 K ranges. T…
Surface Chemistry of Colloidal Platinum: Vibrational Coupling in the Infrared Spectrum of CO Adsorbed on Colloidal Platinum in Liquid Dispersion
Infrared spectra are reported of 12 CO and 12 CO/ 13 CO mixtures adsorbed on colloidal platinum with a mean particle size of 15 Å, stabilized in liquid dispersion by polyvinylpyrrolidone. A shift to higher frequency with increasing coverage of 12 CO is observed in the high-frequency (on-top) CO band, and for 12 CO/ 13…